So on tumblr we're doing Derek/Lydia ship week, and this is one of my three fics for it. You should hop over there and check it out.

Also, a warning, there is knotting in this fic.

Also, I don't own Teen Wolf. :(

Lydia ground her teeth in frustration, plucking at the split of her dress, moving it until she was happy with where it sat against her thigh. She looked in the mirror eyes raking judgementally over her own body, rising to her tippy toes, imagining black heels encasing her feet. She swept her hair up, making a loose knot on the back of her head, a few strands escaping to trail over her neck. The dress was revealing, backless save for half a dozen tiny laces, with a plunging neckline. It would be better suited on Allison with her flatter chest, Lydia decided, but the material felt rich and the cut was stunning for her round hips.

'You look beautiful,' Lisa said from the doorway 'that dress is perfect.'

'It's one of three.' Lydia admitted nodding to the bags waiting for her on the bed. She knew though, as soon as she slid into this one, that this was the one she would wear, but she would keep the others too, she had occasions for them.

'Let's see the rest then.' Lisa said folding her arms and leaning against the wall.

'I like this one.' Lydia wasn't sure why she was arguing this out. There was a beautiful green dress with a hoop skirt and another midnight blue that ended at her knee. Both classy and befitting of a PhD student, but this one held her attention the most.

'I thought you said he wasn't coming?' Lisa licked her lips, eyes following Lydia around the room. Lydia snatched a pair of shoes from her closet. '

'He's not; black peep toe or these sling backs?' Lydia held up the shoes, making her own decision before Lisa could respond.

'Did he say why?' Lisa asked. Lydia snorted. Did Derek Hale ever reason anything vocally? Lydia spent eighty per cent of her time working out what his expressions meant.

'He doesn't like dancing.' That much was true. Derek didn't enjoy the crowd or the press of bodies of a club, he disliked the openness of a dance floor, and how he couldn't see what was going on around him, the noise of a party where smart people do stupid things.

'I say ditch him and find someone fun!' Lisa said poking through one of the bags.

'It's not that simple.' Lydia said examining herself with her shoes on. It wasn't, somewhere between her junior year at college and her graduate degree Lydia had become Derek's mate, his Alpha female. They were an Alpha pair, a family living apart. Beacon Hills was a long track from Harvard but they made it work through various communication channels. Lydia had even spent an afternoon writing a letter to Derek, going as far as spraying the paper with perfume and kissing the seal with red lipstick. Derek had slept with the letter under his pillow for weeks.

'Yes honey it is. Kent wants you. Kent is rich Lydia, he can give you everything you want and need. You two can travel the world together, taste life with him. And I've heard he isn't bad between the sheets.' Lisa said biting at her bottom lip and wiggling her eyebrows.

'You marry him!' Lydia muttered. Isn't bad, Lydia didn't want "isn't bad" in her bed. She wanted amazing, and that's what she had.

'Derek's nice but...' Lisa trailed off.

'But what?' Lydia turned sharp eyes on her.

'He's just good looking, can he hold a conversation?' Lisa asked.

'Better than you'd imagine. Our pillow talk is invigorating. Now get out so I can get back to my thesis.' Lydia snapped, anger suddenly curling in her gut. Derek was an asshole, but he was her Alpha, her boyfriend, her asshole. She didn't appreciate Derek's intelligence being mocked. He was smart, he had two years at Yale under his belt, before things went shit on him again, and Lydia hated that people didn't know that, that Derek had attended Yale. She wanted him to tell people, not for her image but to show people he wasn't a brainless muscle. He was smart; he could be sweet and funny when he wanted to be.

'Lydia, you deserve better.' Lisa said quietly.

'What do you know about my life?' Lydia asked cocking her head to the side.

'I know you wear a mask. I know that you have dreams and ambitions. I know that you don't nearly see as much of him as you want to. I know that you've had your heart broken more than once. I know that you try so desperately to fit into two different worlds, but you don't. Those people back home, they're beneath you, and they don't have your brains or wit. Your world is right here, not with a bunch of rag tag people and a boyfriend who only seems to visit when he needs something from you or it's been too long since his last fuck.'

Lydia opened her mouth to reply but Lisa was already whirling out the door.

'You should really dance with me!' Curtis, one of her students pleaded tugging her hand.

'You should really stop drinking!' Lydia replied removing her hand from his.

'It's a party!' Curtis grinned. Lydia rolled her eyes but she let him lead her to the dance floor. They danced until he grabbed her ass and Lydia sent him on his merry way with a stern threat of finger breaking. She was almost at her seat when Kent appeared, leaning on the chair beside her.

'Hey,' he said his blond hair curling over his collar. He smiled at her, his warm brown eyes crinkling at the corners.

'Hey,' Lydia said with a smile.

'All alone?' Kent asked. Lydia nodded. 'I'm starting to think this Derek doesn't even exist.'

'He's real enough.' Lydia said confidently. Kent nodded and wrapped an arm around her back, warm fingers brushing her skin.

'Dance with me?' Kent pleaded.

'Just one.' Lydia said following him once again to the floor. Kent wrapped an arm around her and pulled her close.

'You know, I would love to take you home with me, show you how you should be treated. If you were my girl I would never ever let you out of my sight.' Kent murmured close to her ear.

'I like my freedom.' Lydia answered.

'That's not what I mean and you know it.' Kent said pressing his cheek to her hair. His fingers were laced at the bottom of her back. Lydia pulled her head away to look into his face as the song ended.

Michael Buble's Home came on, and Lydia bit her lip. That was their song, the one song that Derek danced with her to, at least, he wouldn't start dancing until Home came on but he usually swayed them through several after that, depending on his mood.

A throat cleared behind them. 'Can I have this dance?'

Lydia let go of Kent and whirled around. There he stood, proud and handsome in his black tux, bow tie loose around his neck; because they both knew he had no idea how to tie it properly. His top few buttons were open on the white shirt he wore, a look Lydia more than enjoyed.

'Derek?' Lydia asked with a smile.

'I wanted to pick you up but my flight was delayed.' Derek smiled softly. Lydia lurched forward into his arms, kissing his lips. His hands slid possessively around her back as the kiss deepened. 'You look perfect,' he muttered pulling away from her a fraction.

'You too,' Lydia whispered brushing a crease from his shirt.

'I need you to tie this for me,' Derek indicated the tie, 'I can't get it to work.'

Lydia smiled and pressed a kiss to his lips, her hand wrapped around the back of his neck. 'You're perfect the way you are.'

A throat cleared behind them. Lydia turned to see Kent watching them both with a cold look in his eye. 'Sorry, Derek this is Kent.' Lydia said with a smile as Derek wrapped his left arm around her waist pulling her tight against him.

'Nice to meet you,' Derek said reaching his right hand out to shake, 'I've heard a lot about you.' Kent looked at Derek's outstretched hand, then at Derek and Lydia before wrapping his fingers around it.

'And I you,' Kent said. He glanced at the pair of them, 'if you'll excuse me, I'm sure you have a lot of catching up to do.'

Derek nodded goodbye, wrapping his arms around Lydia and leaning close to her ear. 'Dick,' he murmured.

Lydia slapped his chest but didn't disagree, just fell into the slow dance Derek was leading them through.

'I've missed you,' Lydia said quietly, knowing he would hear her anyway, 'I've been busy but Skype is only good for so much before I miss the feeling of you.'

'I miss your scent. It wore off our bed at home. I miss that.' Derek said, his fingers dancing over her skin.

'I'm happy with you, I love you.' Lydia said. Derek frowned at her but she barrelled on regardless. 'My friends here, they think you're not enough for me, they think I have ambitious plans, and Derek believe me I do. I want to teach, I've applied for jobs back home, and I want to be with you. I want a home and a job and eventually a little family.'

'You've got it all worked out haven't you?' Derek said pressing his lips to her temple.

'I do, I know what I want Derek and you're part of it.' Lydia beamed up at him. 'There's a timetable and everything, I've recorded it in my life plan books.'

Derek snorted and shook his head. 'I don't tell you often enough that I love you do I?' Derek asked her.

'Nope!' Lydia popped the p.

'Well I do.' Derek said dipping his head to kiss her. 'Hey, let's get out of here!'

'You only just arrived,' Lydia teased but she desperately wanted to leave too. She let Derek guide her off the floor, fingers tangled together. The cab ride was quick, and Derek slouched, legs spread taking up as much room as possible, his possessive mood bleeding into the car.

He stripped her reverently once inside the apartment locked safely in her room and she noticed his battered duffle lying on the floor as he kicked his own clothes off. He had already been here before he came to the dance.

Derek's hands were hot on her skin as they explored, teeth nipping all his favourite parts followed by a gentle kiss to sooth the hurt. He paid so much attention to her nipples, kissing and biting that she thought she might come from that stimulation alone.

When he shouldered his way between her legs, pressing her thighs to her chest he bypassed her pussy completely and licked at her asshole. He stayed there for long minutes; tasting and teasing until Lydia was aching to press her thighs together just to find some release, her juices already making her thighs sticky.

Derek didn't let her though; he kept her just where he wanted her, pleading and begging. Her pussy ached, her channel sopping and he hadn't even touched her there, so when he rose up, hovering over her to push into her body she was more than ready.

Lydia came almost as soon as his pubic bone grazed her clit, legs gripping him hard as her orgasm shook through her.

'I want two more of those,' Derek breathed in her ear, 'one when I knot you and the other when I eat your pussy.'

'Fuck!' Lydia shivered, swotting at his ass.

'Such a good girl, all wet for my cock and I haven't even touched your filthy greedy little pussy have I?' Derek teased. The question was rhetorical but Lydia answered him with a shake of her head anyway. He wrapped a hand around the back of her neck; the other braced beside her head and just stared at her.

'What are you waiting for Derek, get on with it, fuck me, knot me!' Lydia demanded. It was what Derek was waiting for, he pulled his hips back then let them snap forward, pushing her up the bed with each thrust.

They moved like that, Lydia trying to keep up but Derek was completely in control, teeth nipping bruises into her throat breath harsh on her skin adding to the sweat pooling all over them, easing the glide together as she clung to him.

Derek's hips stuttered and the tell-tale swelling of his knot caught her off guard. The pressure increased, pressing into Lydia's sweet spot and she came again, her body shuddering around Derek as he locked them together.

'Fuck, baby!' Derek groaned as he started to come, filling her as he rocked with her, but her body carried on seizing again and again until she was wrecked under Derek.

'That was the best...' Lydia trailed off, letting her head rest on the pillow. Derek was busy peppering her with little kisses, licking her sweat damp skin, nosing at his favourite places beneath her chin, behind her ear.

Derek finally pulled out when his knot shrank, and moved quickly between her legs. 'Derek I can't!' Lydia pleaded.

'I know sweetheart, I'm not, just...I want to look,' he sounded almost embarrassed. Lydia ran her fingers through his hair.

'Look all you want,' she whispered cupping the back of his head. He rested his cheek on her thigh, and she felt her eye lids drooping.

It was completely dark when she woke with Derek spooned behind her. His hand was resting over her hip, and she knew what he was thinking, dreaming about.

She only had a few months of her doctorate left, and after that, who knew. She had made plans, but there was nothing wrong with a tweak here and there, especially if it meant she would get more time with her pack.

And who knew, maybe Derek would love Europe for a few months. Lydia smiled and snuggled against him, a new plan forming in her head. Poor Derek didn't know what would hit him.